300 BOTANY. [Ch. XVL 



The following extracts from a note-book show that this 

 point occurred to my father as early as 1837 : 



" Do not plants which have male and female organs together 

 [i.e. in the same flower] yet receive influence from other 

 olants ? Does not Lyell give some argument about varieties 

 being difficult to keep [true] on account of pollen from other 

 plants ? Because this may be applied to show all plants do 

 receive intermixture." 



Sprengel,* indeed, understood that the hermaphrodite 

 structure of flowers by no means necessarily leads to self- 

 fertilisation. But although he discovered that in many cases 

 pollen is of necessity carried to the stigma of another flower, 

 he did not understand that in the advantage gained by the 

 intercrossing of distinct plants lies the key to the whole 

 question. Hermann Mullerf has well remarked that this 

 "omission was for several generations fatal to Sprcngel's 



work For both at the time and subsequently, botanists 



felt above all the weakness of his theory, and they set aside, 

 along with his defective ideas, the rich store of his patient 

 and acute observations and his comprehensive and accurate 

 interpretations." It remained for my father to convince the 

 world that the meaning hidden in the structure of flowers was 

 to be found by seeking light in the same direction in which 

 Sprengel, seventy years before, had laboured. Robert Brown 

 was the connecting link between them, for it was at his 

 recommendation that my father in 1841 read Sprengel's now 

 celebrated Secret of Nature Displayed.^ 



The book impressed him as being " full of truth," although 

 " with some little nonsense." It not only encouraged him in 

 kindred speculation, but guided him in his work, for in 1841 

 he speaks of verifying Sprengel's observations. It may bo 

 doubted whether Robert Brown ever planted a more fruitful 

 seed than in putting such a book into such hands. 



A passage in the Autobiography (p. 44) shows how it was 

 that my father was attracted to the subject of fertilisation : 

 " During the summer of 1839, and I believe during the previous 

 summer, I was led to attend to the cross-fertilisation of flowers 

 by the aid of insects, from having come to the conclusion in 

 my speculations on the origin of species, that crossing played 

 an important part in keeping specific forms constant." 



The original connection between the study of flowers and 



* Christian Conrad Sprengel, born 1750, died 1816. 

 t Fertilisation of Flowers (Eng. Trans.) 1883, p. 8. 

 X Das entdeckte Geheimniss der Natur im Baue und in der Befruchtung 

 der Blumen. Berlin, 1793. 



